首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   134675篇
  免费   11850篇
  国内免费   6941篇
耳鼻咽喉   1259篇
儿科学   2025篇
妇产科学   3070篇
基础医学   14203篇
口腔科学   2758篇
临床医学   16694篇
内科学   21150篇
皮肤病学   1646篇
神经病学   6776篇
特种医学   4445篇
外国民族医学   43篇
外科学   13942篇
综合类   20118篇
现状与发展   21篇
一般理论   20篇
预防医学   9738篇
眼科学   3569篇
药学   14116篇
  118篇
中国医学   6820篇
肿瘤学   10935篇
  2024年   373篇
  2023年   1821篇
  2022年   4271篇
  2021年   5766篇
  2020年   4314篇
  2019年   3904篇
  2018年   4178篇
  2017年   3899篇
  2016年   3462篇
  2015年   5526篇
  2014年   7083篇
  2013年   7245篇
  2012年   10618篇
  2011年   11359篇
  2010年   7758篇
  2009年   6343篇
  2008年   8054篇
  2007年   7995篇
  2006年   7611篇
  2005年   7030篇
  2004年   5001篇
  2003年   4570篇
  2002年   3777篇
  2001年   3184篇
  2000年   2958篇
  1999年   2753篇
  1998年   1364篇
  1997年   1273篇
  1996年   1033篇
  1995年   992篇
  1994年   935篇
  1993年   524篇
  1992年   932篇
  1991年   851篇
  1990年   704篇
  1989年   608篇
  1988年   553篇
  1987年   480篇
  1986年   372篇
  1985年   301篇
  1984年   202篇
  1983年   172篇
  1982年   105篇
  1981年   100篇
  1979年   149篇
  1978年   126篇
  1977年   86篇
  1974年   96篇
  1973年   82篇
  1972年   93篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
OBJECTIVE: To evaluate the relationship between the left ventricular hypertrophy (LVH) and the ambulatory pulse pressure and aortic root dimension (AOD) in essential hypertensive patients. METHODS: We monitored the 24-hour ambulatory blood pressure and applied echocardiography in 107 essential hypertensive patients. Using the left ventricular mass index (LVMI) as an index in evaluating LVH, the patients were divided into 2 groups: 29 cases in the LVH group and 78 in the non-LVH group. RESULTS: The average levels of 24-hour pulse pressure, daytime pulse pressure, nighttime pulse pressure and AOD were significantly different between patients with LVH and without LVH (P < 0.05). Multiple stepwise regression analysis showed that the changes in nighttime pulse pressure and AOD were closely related to LVMI (P < 0.001). CONCLUSION: The pulse pressure and AOD are important factors leading to LVH in patients with essential hypertension.  相似文献   
72.
Skin penetration of topically applied diclofenac is important for the treatment of rheumatic diseases and actinic keratoses. We have studied the permeation of diclofenac across human cadaver epidermis in-vitro from four lecithin vesicle formulations and a few marketed semi-solid preparations. The lecithin vesicle formulations were prepared by dissolving the lipid contents (lecithin and sodium cholate) in a 1:1 mixture of methanol-chloroform, evaporating the solvents under vacuum, and hydrating the lipid layer with the drug solution in water or 10% ethanol. The vesicles were sonicated for 5 min to reduce the vesicle size and their size and Zeta potential were characterized. The cumulative amount and maximum flux of diclofenac was 69.7+/-40.3 micrograms and 4.77+/-3.16 micrograms/hcm(2) from lecithin vesicles containing sodium cholate and 10% ethanol, and is the highest of all formulations studied. The cumulative amount and mean maximum flux obtained from other formulations were in the range of 2.46+/-1.98-29.9+/-10.1 micrograms and 0.53+/-0.46-3.61+/-0.86 micrograms/hcm(2). Based on the results, lecithin vesicles of diclofenac appear to be advantageous for the topical delivery of diclofenac.  相似文献   
73.
糖尿病患者超声乳化白内障吸除手术的临床观察   总被引:4,自引:0,他引:4  
李林  姚达强  郭露萍 《眼科学报》2003,19(2):98-100
目的:探讨糖尿病患者进行超声乳化白内障吸除联合人工晶状体植入手术的临床效果。方法:50例(61只眼)糖尿病患者(设为A组)和同期163例(174只眼)血糖正常患者(设为B组)接受超声乳化白内障吸除联合人工晶状体植入手术。糖尿病患者手术前通过饮食疗法、口服药物或肌注胰岛素治疗,使空腹血糖降到 10mmol/L以下。术后随访 1~28个月(平均 8.6个月),复查视力、裂隙灯及眼底检查。结果:术后矫正视力≥0.5者,A组为77.1%;B组为80.5%。两组经统计学处理差异无显著性(P>0.05)。两组术中出现后囊破裂及术后发生角膜水肿和前房渗出等并发症的差异无显著性(P>0.05 )。结论:糖尿病患者进行超声乳化白内障吸除手术前只要有效控制血糖,其手术效果与对照组患者相同。但术后血糖的控制仍然十分重要。眼科学报2003;19:98-100。  相似文献   
74.
75.
76.
77.
Selecting an appropriate working correlation structure is pertinent to clustered data analysis using generalized estimating equations (GEE) because an inappropriate choice will lead to inefficient parameter estimation. We investigate the well‐known criterion of QIC for selecting a working correlation structure, and have found that performance of the QIC is deteriorated by a term that is theoretically independent of the correlation structures but has to be estimated with an error. This leads us to propose a correlation information criterion (CIC) that substantially improves the QIC performance. Extensive simulation studies indicate that the CIC has remarkable improvement in selecting the correct correlation structures. We also illustrate our findings using a data set from the Madras Longitudinal Schizophrenia Study. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
78.
79.
Reduction of transmission of human immunodeficiency virus type 1 (HIV-1) through human milk is needed. Alkyl sulfates such as sodium dodecyl sulfate (SDS) are microbicidal against HIV-1 at low concentrations, have little to no toxicity, and are inexpensive. The authors have reported that treatment of HIV-1-infected human milk with < or = 1% (10 mg/mL) SDS for 10 minutes inactivates cell-free and cell-associated virus. The SDS can be removed with a commercially available resin after treatment without recovery of viral infectivity. In this article, the authors report results of selective biochemical analyses (ie, protein, immunoglobulins, lipids, cells, and electrolytes) of human milk subjected to SDS treatment and removal. The SDS treatment or removal had no significant effects on the milk components studied. Therefore, the use of alkyl sulfate microbicides to treat milk from HIV-1-positive women may be a simple, practical, and nutritionally sound way to prevent or reduce transmission of HIV-1 while still feeding with mother's own milk.  相似文献   
80.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号